1. FIELD OF THE INVENTION
The invention relates to a testing system for a pilot operated, pressure relief valve which can be utilized to determine the setpoint of the relief valve without removing the relief valve from the line in which it is connected, or opening of the pressure relief valve.
2. SUMMARY OF THE PRIOR ART
Pilot operated safety valves or pressure relief valves are incorporated in practically every tank or line carrying fluid under substantial pressures. Various governmental agencies require the periodic testing of the setpoint of such pressure relief valves, or in other words, the line pressure at which the pilot will be actuated to in turn effect the opening of the pressure relief valve to vent the line the pilot which will close the opened relief valve.
Two types of pilot operated relief valves are currently in use. One is a modulating, non-flowing pressure operated relief valve of the type shown in U.S. Pat. No. 4,615,356. This valve incorporates as part of its structure a field test valve which requires the addition of a source of test pressure to make the test valve operable. Obviously, the incorporation of a test substantially increases the cost of such safety valves. Other testing arrangements require the removal of the entire valve from the system or the determination of the set pressure and closing pressure of the pilot operated safety valve by venting system media, which is highly undesirable. Flowing, modulating pilot valves present similar problems for determining the pilot setpoint.
There is a need therefore for a test valve system for pilot operated safety valves which is portable and which will effect the determination of the setpoint of the pilot of such safety valve, whether of the flowing or non-flowing type, without requiring the removal of the safety valve from the system or the venting of system media.